United States Patent 3,346,670 METHOD FOR THE PREPARATION OF PHOSPHATE ESTERS John G. Papalos, Fort Worth, Tex., assignor to General Aniline & Film Corporation, New York, N.Y., a corporation of Delaware No Drawing. Filed Dec. 11, 1962, Ser. No. 243,721 11 Claims. (Cl. 260980) This invention relates to the preparation of organic phosphorus-bearing compounds and relates more particularly to an improved process for preparing phosphate-free acid esters of nonionic surface active agents.

The particular nonionics of interest in the process of the instant invention are the nonionic surface active agents having the molecular configuration of a condensation product of at least one mole of an alkylene oxide with one mole of a compound containing at least 6 carbon atoms and a reactive hydrogen atom are preferably polyoxyalkylene derivatives of alkylated and polyalkylated phenols, multi-branched chain primary aliphatic alcohols having the molecular configuration of an alcohol produced by the oxo process from a polyolefin of at least 7 carbon atoms, and straight chain aliphatic alcohols of at least carbon atoms. The alkylene oxide may be propylene oxide, butylene oxide or preferably ethylene oxide. Examples of these derivatives and other suitable nonionic surface active agents which may be phosphated in accordance with the present invention are included below. In this list, E.O. means ethylene oxide and the number preceding same refers to the number of moles thereof reacted with one mole of the given reactive hydrogen containing compound.

Nonylphenol-i-9-11 E.O. Nonylphenol+2 E.O. Dinonylphenol+7 E.O. Dodecylphenol+18 E.O. Castor 0il|20 E.O. Tall oil+18 E.O. Oleyl alcohol+20 E.O. Lauryl alcohol +4 E.O. Lauryl alcohol+ E.O. Hexadecyl alcohol+ 12 ED. Hexadecyl alcohol+ E.O. Octadecyl alcohol+20 E.O. Oxo tridecyl alcohol:

(From tetrapropylene) +7 E.O. (From tetrapropylene) +10 E.O. (From tetrapropylene) +15 E.O. Dodecyl mercaptan+9 E.O. Soya bean oil amine+10 E.O. Rosin amine+32 E.O. Coconut fatty acid amine+7 E.O. Cocoa fatty acid+10 E.O. Dodecylbenzene sulfonamide+10 E.O. Decyl sulfonamide-i-G E.O. Oleic acid-i-S E.O. Polypropylene glycol (30 oxypropylene units)+10 E.O.

It can be seen from the above exemplary nonionics that the optimum starting materials are those selected from the group consisting of phenol, alkyl phenols, alphatic alcohols, fatty acids, fatty amines, fatty amides, rosin amines, long chain sulfonamides, long chain-substituted aryl sulfonamides, and high molecular weight mercaptans.

Nonionic surface active agents such as those of the instant invention have been previously esterified with a number of different phosphating agents, including phosphorus trichloride, PCl phosphorus oxychloride, P001 and phosphorus pentoxide, P 0 Esters produced from the chlorine-containing phosphating agents, such as the phosphorus trichloride and the phosphorus oxychloride, contain bound chlorine atoms which are undesirable in many applications. The perferred phosphating agent used in most instances heretofore has been phosphorus pentoxide. However, the product yield of phosphate esters resulting from the conventional phosphation reactions employed heretofore, with phosphorus pentoxide as a phosphating agent, has been relatively poor, especially with the higher molecular weight nonionic surface active agents. As much as of the organic starting material has failed to be converted to its respective phosphate esters with the prior art processes.

It is an object of the instant invention to provide a process for the preparation of phosphate esters from nonionic surface active agents free from the foregoing and other disadvantages.

A further object of this invention is the provision of a process for the preparation of phosphate esters of nonionic surface active agents wherein a much higher percentage of the organic starting materials will be converted to phosphate esters.

Other objects and advantages of the instant invention will appear from the following detailed description and the appended claims.

Nonionic surface active agents such as those of the instant invention have been converted heretofore to their phosphate esters by first azeotropically distilling the compounds to remove all traces of water and then reacting the dried compound with phosphorus pentoxide under anhydrous conditions. The removal of water prior to the phosphation process has been considered necessary to prevent the formation of phosphoric acid by reaction of the water with the phosphorus pentoxide. The presence of phosphoric acid during the phosphation reaction has previously been believed to be disadvantageous to a satisfactory phosphation. While it has been recently discovered that phosphation in the presence of certain phosphorus-containing compounds, such as hypophosphorous acid and salts thereof, and phosphorous acid and salts and esters thereof, will improve the color of the reaction products, the presence of water or phosphoric acid has been carefully avoided.

It has now been unexpectedly discovered that the introduction of small quantities of water into the nonionic surface active agents prior to reacting the same with phosphorus pentoxide will produce a reaction product containing much higher concentrations of phosphate esters than the products of prior art processes. While it has been recognized previously that the presence of Water in the nonionic surface active agents affects the ratio of the products and by-products in the reaction mixture, it has not been realized heretofore that incorporation of Water will greatly increase the conversion of the nonionic sur-.

face active agents to its phosphate esters.

As previously mentioned, it is believed that water pres cut during the phosphation reaction reacts with the phosphorus pentoxide to form phosphoric acid. It is hypothesized that the acid formed by the addition of water prior to phosphation, in accordance with the process of the instant invention, catalyzes the phosphation reaction and produces an increased yield of phosphate esters. This hypothesis was substantiated by adding small amounts of mineral acids, such as phosphoric, sulfuric, hydrochloric, boric, bromic, hydrobromic, hypobromous, hypophosphoric, metaphosphoric and pyrophosphoric acids and the like to the nonionic surface active agents in lieu of the water. It was found that the addition of these acids produced an increase in the conversion of the nonionic surface active agents to its phosphate ester comparable to the higher yield produced by the addition of Water. It can therefore be seen that it has been surprisingly discovered that addition of either water or a mineral acid to the nonionic surface active agents prior to the phosphation process, as set forth hereinabove, will result in an increased conversion to the phosphate ester. The invention is not to be restricted to the particular method by which the mineral acid is introduced into the nonionic surface active agents. The preferred mineral acids are phosphoric, sulfuric and hydrochloric. However, the preferred embodiment of the instant invention is the addition of water rather than a mineral acid to the dried nonionic surface active agents, since the former additive is obviously more economical and avoids the necessity of incorporating acids which are foreign to the reaction mixture.

Increased conversion has been realized by adding from 0.001 to 3% by weight of water or mineral acid, based on the weight of the dried nonionic surface active agents. The preferred percentage of additive, however, is between 0.1 and 0.8%

The reaction products of the process of the instant invention are believed to be a mixture of the orthophosphates and pyrophosphates of the nonionic surface active agents starting materials. Phosphate esters of various nonionic surface active agents have found numerous commercial applications such as detergents, lubricants, oil additives, antistatic agents, foaming agents, corrosion inhibitors and the like. Moreover, many of the phosphate esters have shown multiple applications when they contain higher concentration of phosphates. The importance of the discovery of the instant invention which makes possible the production of such high concentration phosphate products is readily seen.

Good conversion to the phosphate esters has been especially difiicult heretofore with the higher molecular weight nonionic surface active agents. That is, the phos phate esters of the higher homologues of the nonionic surface active agents used in the instant invention have been considered more diflicult to prepare using prior art techniques. The increased conversion produced by the addition of small amounts of water, in accordance with the preferred mode of this invention, is therefore especially important commercially in this instance, since many of the phosphate esters of the higher molecular weight nonionic surface active agents are desired in the various applications set forth hereinabove.

An additional advantage realized by adding small amounts of water to the dried nonionic surface active agent prior to treatment "with phosphorus pentoxide is that previous attempts to use higher percentages of this phosphating agent to increase the yield of phosphate esters have not been successful. It has been discovered that the conversion has not been increased heretofore by a higher concentration of the phosphorus pentoxide because this phosphating agent has formed lumps when added in excess to the dried nonionic surface active agent. The addition of small amounts of water prior to phosphation has been found to eliminate this phenomenon of lumping. The prior art phosphation processes have reacted one mole of phosphorus pentoxide with from 2 to 4.5 moles of the nonionic surface active agent. It is now found that a ratio of from 1 to 3 moles of phosphorus pentoxide to Example 1 Procedure A.Into a two liter, electrically heated, reaction flask, fitted with an agitator, a thermometer,.and a water separator fitted to a reflux condenser, is charged 600 parts of nonylphenol containing fifteen moles of ethylene oxide (0.682 moles of the nonionic surface active agents) and 200 parts of xylene. The mixture is heated to reflux until water is completely removed from the reaction mixture. The xylene is then removed by distillation and the dried nonionic surface active agents are cooled to 50 C. The apparatus is then re-arranged so that inert gas is bubbled through the reaction mixture and a vent is kept open. While using an agitator speed of 400 revolutions per minute, 150 parts (0.358 moles) of phosphorus pentoxide is added over a period of one and one-half hours. The temperature of the reaction mixture is maintained at 70-95 C. during this period. The reaction mixture is then heated to 120130 C for five hours. This mixture is then cooled to 90 C. and discharged. The final product is analyzed by means of a conventional ion exchange procedure. There is found to be 9.38 percent of unreacted nonionic surface active agent.

Procedure E.The same charge and procedure as in A above is employed, except that after the water is removed, there is added 2.5 parts of water to the dried nonionic surface active agents. Analysis of the product by an ion exchange procedure showed 2.34 percent of unreacted nonionic surface active agents.

Procedure C.-Procedure A is repeated except, after the water is removed, there is added 3 parts of phosphoric acid to the dried nonionic surface active agents. The unreacted nonionic surface active agents of the resulting product is 1.15 percent.

Procedure D.Procedure A is repeated except, after the water is removed, there is added 3 parts of hydrochloric acid (chemically pure) to the dried nonionic surface active agents. The unreacted nonionic surface active agent in the phosphated product is 3.0 percent.

Procedure E.Procedure A is repeated except, after the water is removed, there is added 4.8 parts of sulfuric acid (chemically pure). The resulting product is found to contain 2.5 percent of unreacted nonionic surface active agent.

Procedure F.Procedure A is repeated except, after the water is removed, there is added 4.8 parts of water to the dried nonionic surface active agent. There is found 2.0 percent of unreacted nonionic surface active agent in the resulting product.

Procedure G.Procedure A is repeated except, after the water is removed, there is added 0.6 part of water to the dried nonionic surface active agent. There is found 2.5 percent of unreacted nonionic surface active agent in the resulting product.

As seen from the above example, the Procedures B, C, D, E, F, and G yielded comparable results. This evidences the fact that the improved conversion is catalyzed by the presence of a mineral acid which can be added directly to the dried nonionic surface active agent or formed by the addition of water. It is also readily seen from the above results that even trace amounts of additives provide substantially increased conversion to the phosphate ester.

The reaction temperature is not limited to 120130 C. as shown in Procedure A but can be as high as 200 C. The pressure may be atmospheric, subatmospheric or superatmospheric. The only limitation on the reaction conditions is that the temperature and pressure are'such that the added water or mineral acid is not driven olf during the reaction.

The following table lists the pertinent data on several phosphate esters prepared by our preferred Procedure B 1 water is added in an amount between 0.1 and 0.8 percent based on the weight of said nonionic surface active agent. 5. A process for the preparation of phosphate esters comprising reacting one mole of phosphorus pentoxide and compares them with products prepared according with 0.3 to 2 moles of a nonionic surface active agent to Procedure A as a control.

having the molecular configuration of a condensation Percent Percent Molar Ratio Parts by Unreacted Unreacted of Nonionic Weight of Example M.W. Structural Formula of Nonionic Nonlonic Noniom'c Surface Nomomc Surface Active Agent Surface Agent Surface Agent Active Agents Surface Active Agent by Agent by to P Agents to Procedure A Procedure B Parts of P20 2, 420 O9H19CBH4 OC2H4 5ILOH 44. 7 12. 9 1:3 5. 7:1 1, 498 C6H13C6H4(OC2H4)30-OH 25. 2 4. 6 1:3 3. 5:1 C36H73C6H4(0CH 18. 5 6. 3 1:2 4. 5:1 30.0 5.0 1.5:1 10:1 35.0 6.8 1.511 13:1 20.0 4.5 1.99:1 12:1 93.0 84.2 121.5 32:1 5.2 1.7 1.921 8.921 8.4 1.3 L911 14:1 6.3 2.0 1.9:1 12:1 11.2 1.2 1.921 18:1 75.5 30.0 1:3 9.621 95.1 50.2 1:3 16:1 3.6 1.6 1.911 8.221 15.4 5.9 1:1 11.5:1 3.5 1.2 1.921 7.7:1 CsH|o(OC2H )-2o.OH 26.0 6. 0 1.5:1 10:1 1, 918 (C1BH37)2C6H3(OC2H4)30 H 12. 1 7. 3 121 13. 5:1 1, 236 CgzH45(OC2I'I-|)zu-0H 19. 4 6. 2 1: 1 8. 7:1

The increase in conversion by the incorporation of water prior to phosphation is clearly seen from the above table. It will be noted that extremely high percentages of unreacted nonionic surface active agent were present in the reaction products of the higher molecular weight nonionic surface active agents produced according to Procedure A, especially those having a molecular weight in excess of 2,000, and that substantially improved conversion resulted in most instances from the use of Procedure B. It is also of special interest that the molar ratio of the nonionic surface active agent to the phosphorus pentoxide is from one to two moles of nonionic surface active agent to from one to three moles of pentoxide, a ratio heretofore believed disadvantageous. N

It is to be understood that the foregoing detailed description is given merely by way of illustration and that many variations may be made therein without departing from the spirit of this invention.

What is hereby claimed and desired to be secured by Letters Patent is: I

1. A process for the preparation of phosphate esters comprising reacting phosphorus pentoxide with ethoxylated nonyl phenol or an ethoxylated aliphatic alcohol containing at least 6 carbon atoms, wherein a small amount of water is added to said ethoxylated nonyl phenol or aliphatic alcohol prior to the reaction with phosphorus pentoxide.

2. A process for the preparation of phosphate esters comprising reacting one mole of phosphorus pentoxide with 0.3 to 2 moles of a nonionic surface active agent having the molecular configuration of a condensation product of at least one mole of alkylene oxide and one mole of a compound containing at least 6 carbon atoms and a reactive hydrogen atom, and selected from the group consisting of phenol, alkyl phenols, aliphatic alcohols, fatty acids, fatty amines, fatty amides, rosin amines, long chain sulfonamides, long chain-substituted aryl sulfonamides, and high molecular weight mercaptans, wherein .001% to 3% by weight of water is added to said nonproduct of at least one mole of alkylene oxide and one mole of a compound containing at least 6 carbon atoms and a reactive hydrogen atom, and selected from the group consisting of phenol, alkyl phenols, aliphatic alcohols, fatty acids, fatty amines, fatty amides, rosin amines, long chain sulfonamides, long chain-substituted aryl sulfonamides, and high molecular weight mercaptans, wherein .001% to 3% by weight of a material selected from the group consisting of Water and a mineral acid selected from the group consisting of phosphoric, sulfuric, hydrochloric, boric, bromic, hydrobromic, hypobromous, hypophosphoric, metaphosphoric and pyrophosphoric acids is added to said nonionic surface active agent prior to the reaction with phosphorus pentoxide.

6. A process in accordance with claim 5, wherein said alkylene oxide is ethylene oxide.

7. A process in accordance with claim 5, wherein said material is added in an amount between 0.1 and 0.8 percent based on the weight of said nonionic surface active agent.

8. A process for the preparation of phosphate esters comprising azeotropically distilling a nonionic surface active agent having the molecular configuration of a condensation product of at least one mole of alkylene oxide and one mole of a compound containing at least 6 carbon atoms and a reactive hydrogen atom and selected from the group consisting of phenol, alkyl phenols, aliphatic alcohols, fatty acids, fatty amines, fatty amides, rosin amines, long chain sulfonamides, long chain-substituted aryl sulfonamides, and high molecular weight mercaptans, to remove any water present therein, drying said nonionic surface active agent, adding to the dried nonionic surface active agent .001% to 3% by weight of water and then reacting 0.3 to 2 moles of said nonionic surface active agent with one mole of phosphorus pentoxide.

9. A process in accordance with claim 8, wherein said nonionic surface active agent is a nonylphenol containing fifteen moles of ethylene oxide.

10. A process in accordance with claim 8, wherein said water is added in an amount between 0.1 and 0.8 percent based on the Weight of said nonionic surface active agent.

11. A process in accordance with claim 8, wherein said nonionic surface active agent has a molecular weight in excess of 2,000.

References Cited UNITED STATES PATENTS 2,853,471 9/1958 Beadell 260-980 X 3,004,056 10/1961 Nunn et a1. 260-980 X Nunn 260980 Clarke et a1 260-980 X Chiddix et a1 260980 X Sorstokke et a1. 260-974 5 CHARLES B. PARKER, Primary Examiner.

I. MARCUS, Examiner.

F. M. SIKORA, R. L. RAYMOND, Assistant Examiners.